This study was conducted to obtain basic data to evaluate the applicability of geopolymers as absorbers for suspended solids (SS) in rainwater. Geopolymer absorbers were prepared by integrated gasification combined cycle fused slag and Si sludge. The SS removal percentages were determined and compared on the basis of the porosity, size, and density of the absorbers. The maximum SS removal percentage of the geopolymer absorber with a density of 0.9 g/cm³ and pore sizes ranging from ~123 to 909 μm was 91.0%, which meets the standard value for commercial absorbers in Korea. Although the geopolymer absorbers had low densities and large pore sizes, the SS removal percentage did not increase as the density decreased; this is because of the resulting low compressive strength and high fracture rate, which typically leads to the formation of small particles and increases SS concentration in rainwater.

Keywords: Geopolymer absorber, IGCC fused slag, Si sludge, SS removal percentage